Today, overmolded electronic assemblies are manufactured by adhesively mounting a substrate, e.g., a printed circuit board (PCB) assembly to a backplate with a structural adhesive and attaching an integrated circuit (IC) die, e.g., a flip-chip, to a heatsink pedestal of the backplate with a thermally conductive adhesive. In general, a heat cycle, e.g., 150° C. for 20 minutes, is utilized to cure the adhesives prior to an overmolding process. The structural adhesive bonds areas of the PCB that are not populated to corresponding support pedestals on the backplate. As such, the bonded area between the PCB and the backplate is limited. Furthermore, the strength of most structural adhesives is marginal at common molding temperatures, e.g., 165° C. Due to the fact that the structural bond area is limited and the strength of the structural adhesive is marginal at overmolding temperatures, minor movements of the PCB may occur during the overmolding process. As the flip-chip is bonded to a heatsink, with a thermally conductive adhesive, movement of the PCB can lead to fractured flip-chip solder bumps.
FIG. 1 depicts an exemplary prior art backplate 10, including a structural adhesive 14 applied to a lip (i.e., a peripheral pedestal) 12 of the backplate 10. The structural adhesive 14 is also applied to a plurality of integral support pedestals 20, which support a PCB, when mounted to the backplate 10. As is shown, a thermally conductive adhesive 18 is applied to a plurality of integral heatsinks 16, which are utilized to heatsink IC dies, which are electrically coupled to the PCB (not shown in FIG. 1). It should be appreciated that both the adhesive dispense and adhesive cure steps require material and process time to implement.
What is needed is a technique for manufacturing an overmolded electronic assembly that does not require a structural adhesive to bond a substrate to a backplate. Furthermore, it would be desirable if the technique did not require a thermally conductive adhesive to thermally connect an integrated circuit (IC) die of the substrate to an integral heatsink of the backplate.